The present invention pertains generally to organic energetic material synthesis and in particular to the synthesis of nitrated aromatic aza-compounds from diaminobenzene.
One nitrated aromatic aza-compound that has exceptional thermal stability and high energy content is tetranitrodibenzo-1,3a,4,6a-tetrazapentalene. This compound is used as a primer for energetic gas-producing devices, especially for cartridges used in cartridge-activated devices, e.g. canopy-release for fighter aircraft.
Presently the use of this compound has been restricted on account of the high cost. The compound is usually prepared by nitrating dibenzo-1,3a,4,6a-tetrazapentalene which is prepared by the method disclosed in U.S. Pat. No. 2,984,544, now U.S. Pat. No. Re. 25,238 and in U.S. Pat. No. 3,197,475 by Rudolf A. Carboni. Dibenzotetrazapentalene is prepared by the steps comprising oxidizing diaminoazobenzene to diazidoazobeneze by sodium azide and nitrous acid, and thermally cracking the azide substituents of diazidoazobenzene to form dibenzotetrazapentalene.
The diaminoazobenzene synthesis is disclosed in Carboni et al. JACS 89 p. 2618 (1967). By this method oxidation is carried out in benzene and product purification or isolation is achieved by extraction with methylene chloride. These two techniques contribute much to the high cost of the final product in that the reaction proceeds slowly, the yields are low, the purification is extremely slow, and the use of benzene requires many safety precautions.